Short answer is that an enema is best but takes more time than most of us have. I find it preferable to empty the bowel completely but you can get away with sluicing your anus with an anal syringe or the like. Depends a lot on your bowel movements - if you can get a regular large movement (sorry, not the best thought I know!) then it helps a lot. Fibre, fruit and regular paced meals help achieve this. But if you have an irregular and small movement then you may find just sluicing a little messy depending a lot on the level of excitement you reach. Unfortunately you may find that as you enjoy your Aneros you may find that some stool left decides to exit. It happens, which is why a full enema is best. And it encourages you to relax and take time, which in turn gives a greater benefit form the Aneros.